U-Line Ice Maker Error Code L Zone T Short

The L Zone T Short error on a U-Line ice maker indicates that the left zone thermistor circuit has shorted. A thermistor is a temperature-sensing resistor whose resistance changes predictably with temperature. When the control board reads a shorted condition in this circuit, it means the resistance has dropped to near zero ohms, which the board interprets as an implausibly high temperature reading or a failed sensing circuit. The left zone thermistor is responsible for monitoring temperatures in that specific compartment of the unit, and the control board relies on accurate readings to manage the refrigeration and ice-making cycles.

A shorted thermistor circuit is most often caused by physical damage to the thermistor cable itself. The wiring can become pinched against a cabinet edge, a refrigerant line, or a mechanical component during installation or servicing. Over time, insulation can wear through at pinch points, causing the two conductors to contact each other and create a short circuit. Moisture intrusion is another common contributor, as condensation or ice buildup around the sensor lead can create a conductive path between wires or between a wire and ground.

Diagnosing this fault begins with a careful visual inspection of the thermistor cable, tracing it from the sensor tip back to the wiring harness connector. Look for any areas where the cable is compressed, abraded, or shows signs of melted insulation. If the cable appears intact, the thermistor itself may have failed internally. Resistance testing across the thermistor leads at a known temperature can confirm whether the component is shorted. A properly functioning thermistor will show measurable resistance that correlates with ambient temperature rather than a near-zero reading.